Polyvinyl alcohol is a polyhydroxy polymer having a polyethylene backbone with pendent hydroxyl groups. Polyvinyl alcohol is made by the partial or complete hydrolysis of polyvinyl acetate. During hydrolysis, the acetate groups are removed and replaced with hydroxyl groups.
Polyvinyl alcohol is a very useful polymer that has numerous applications. For instance, polyvinyl alcohol has excellent film forming properties and has excellent emulsifying properties. In addition, polyvinyl alcohol can be used in many different adhesive formulations in order to improve the adhesive properties of the resulting compositions. Of particular advantage, the properties of polyvinyl alcohol can be altered and tailored to a particular application by changing the degree of hydrolysis and/or by adjusting the molecular weight of the polymer.
Polyvinyl alcohol, for instance, is used as an additive in latex paints, paper coatings, hairsprays, shampoos and adhesives. Polyvinyl alcohol is also used as a gas barrier in polymer films, such as polyester films. Polyvinyl alcohol has also been used as a mold release agent, as a film in packaging materials, as a reinforcement additive in construction materials such as concrete, and as an additive in fiberglass.
In many applications, polyvinyl alcohol is incorporated into the product in the form of a solution. For instance, polyvinyl alcohol is typically dissolved in a solvent, such as water, prior to being incorporated into a product. Although polyvinyl alcohol is generally water soluble, problems have been experienced in the past in forming the polymer solutions since the polymer is hard to wet. In addition, the polymer has a tendency to form clumps when combined with various solvents. Thus, in the past, polyvinyl alcohol particles were combined with water in a blend tank under controlled conditions. While being agitated, the mixture of the polyvinyl alcohol particles and the water was typically heated using, for instance, steam sparging or jacket heating to an elevated temperature that assisted in dissolving the solid material.
After being dissolved in a solvent, the resulting polyvinyl alcohol solution was then typically transported to a manufacturing facility for use in various processes. For example, dissolved polyvinyl alcohol is used extensively in formulating starch adhesives. The starch adhesives may, for instance, be used in the construction of corrugated materials.
Pre-dissolving the polyvinyl alcohol particles in water as described above, however, has created various inefficiencies. For instance, the above process for dissolving polyvinyl alcohol particles into a solvent can require significant amounts of energy that adds substantial cost to the product. In addition, transportation inefficiencies are realized in that large amounts of solvent, such as water, are transported with the polyvinyl alcohol product to the manufacturing facility.
In addition to having to transport large amounts of solvent, the containers used to transport the polymer solution also can add significant cost to the product. For example, polyvinyl alcohol solutions are typically transported to manufacturing facilities in two hundred to three hundred gallon totes. Once the totes are used at the manufacturing facility and emptied, the empty totes are then typically transported back to the location where the polymer solutions are formed. Thus, not only the totes themselves are expensive and add cost to the product but transporting the empty totes further creates expenses that must be borne by manufacturers and suppliers.
In view of the above, a need currently exists for improved methods and processes for marketing polyvinyl alcohol additives and for incorporating the additives into useful products.